Brown Patch (Rhizoctonia Blight)
Evidence of brown patch in your lawn
The fungus Rhizoctonia solani causes Brown Patch. It affects all common turfgrasses and is a major disease of tall fescue and perennial ryegrass, normally occurring in late spring and summer.
Signs and Symptoms:
Brown patch causes circular patches of light brown turf that are six inches to two or more feet in diameter. Light brown lesions with dark brown, irregular borders occur on the leaf blades themselves and the areas beyond the leaf lesions may be dark in color.
Favorable Conditions:
Moist conditions are favorable to most fungal diseases. From heavy dew, rain or improper irrigation that keeps turf wet for prolonged periods. This disease more commonly affects sunny areas. It occurs when temperatures are seventy-five to eighty-five degrees Fahrenheit during the day, and nighttime temperatures stay above sixty-five degrees Fahrenheit.
Cultural Prevention and Control:
To help minimize this disease, avoid evening or nighttime watering from June through August. However, if this is the only available time to water, by all means, do the watering.
Over-the-counter products to control brown patch include Bayleton and Spectracide Immunox. These provide 7-14 day control. For month-long control with a commercial product call Ryan Lawn & Tree.